Near net shape fabrication of porous cordierite by combination of foam gel‐casting and freeze‐drying

Abstract Near net shape fabrication of porous cordierite was successfully achieved through a combination of foam gel‐casting, freeze‐drying, and in situ synthesis. Environment friendly gelation was used as gel system, and the gelatin concentration influenced the drying shrinkage vastly. Combined with the volume expansion coming from phase transition and solid reaction during in situ synthesis of cordierite, the total linear shrinkage could be controlled around zero (−1.87% to 0.45%) by adjusting the gelation concentration and solid content in the slurry, meanwhile the prepared porous cordierite ceramics showed both high porosity (85.9%–91.1%) and high compressive strength (0.58–3.37 MPa). The sample with 0.05 g/ml gelatin concentration and 20 vol% solid content possessed excellent performance: total porosity of 89.1%, compressive strength of 1.36 MPa, and specific strength of 4.9 MPa/(g/cm ³ ), showing the potential usage of filter carrier.